DE10014879B4 - Method for controlling a dual-clutch transmission or the engine speed of a dual-clutch transmission - Google Patents

Abstract

Method for controlling a dual clutch transmission (1) with two input shafts (E1, E2), the first input shaft (E1) being assigned a first friction clutch (K1) and the second input shaft (E2) being assigned a second friction clutch (K2) and with the help of each friction clutch ( K1, K2) a drive train can each be implemented, with the friction clutches (K1, K2) transmitting an engine torque from the respective input shaft (E1, E2) via the respective drive train to the output shaft (7), with the transmission (1) at least has two gear stages, the first gear stage is formed at least by a first gear pair and the second gear stage is formed at least by a second gear pair, and the gear stage change by disengaging and / or engaging at least one sliding sleeve which can be at least partially engaged with the first or second gear pair (6 , 8, 9) and wherein the engine speed (ω) is changed as a function of the gear to be engaged, whereby The control of the engine speed during the gear change with the aid of at least one of the two friction clutches (K1, K2) is characterized in that the drive train includes the first closed friction clutch (K1) both in the engaged first gear and in the engaged second gear, and that during the gear change from the first to the second gear, the second friction clutch (K2) is at least partially closed and the drive train is formed via the second friction clutch (K2), the second input shaft (E2), a third gear pair and the output shaft (7).

Description

The invention relates to a method for controlling a dual-clutch transmission with two input shafts, wherein the first input shaft, a first friction clutch and the second input shaft, a second friction clutch is assigned and with the aid of each friction clutch in each case a drive train can be realized, wherein of the friction clutches an engine torque from the respective input shaft is transmitted via the respective drive train to the transmission output shaft, wherein the transmission has at least two gear ratios, the first gear at least by a first gear pair and the second gear at least formed by a second gear pair and the gear stage change by the disengagement and / or engagement of at least one realized with the first or second gear pair at least partially engageable sliding sleeve and wherein the engine speed is varied depending on the gear ratio to be engaged.

In the prior art, from which the invention proceeds ( DE 197 17 042 A1 ), a method for switching a synchronizer-free change gear is described. In this method, a predetermined speed difference is set for switching a synchronizer-free gear change gear to the gear clutches in the range of synchronous speed, so that always come in one and the same direction opposite engagement flanks of the coupling halves during switching in contact. Furthermore, an engine control unit is provided, wherein the engine torque is initially increased in coasting mode and the significant value of the engine speed of a predetermined speed difference is assigned to the gear couplings such that the respective drive side coupling half in all circuits either always higher or always the lower speed compared to the speed the output side coupling half, in particular a corresponding speed difference between 10 U / min to 40 U / min is present.

Nevertheless, the gear stage change in the transmission described here is not yet optimally formed, namely the control of the engine speed during the gear stage change is not optimal. Although it is attempted to perform a more optimal realization of a gear stage change due to a given differential speed, the control of the engine speed during the gear stage change is very expensive. Although a gearbox control unit or an engine control unit must almost always inevitably be provided in accordance with automatic motor vehicle transmissions, such as a dual-clutch transmission, the regulation of the engine speed via the engine control unit is very complicated and depends on different different parameters. a. depending on the gear ratio to be engaged always regulated accordingly. Thus, in the prior art in a gear ratio change often also to "load changes beats" because during the gear stage change the drive train to the vehicle wheels temporarily torque-free and the next gear is engaged after the engine speed is changed or adjusted by the engine control unit, so that After inserting the further gear, the output gears are again subjected to a torque.

The DE 196 31 983 C1 discloses a method for changing gears in a dual-clutch transmission from the first gear to the second gear in different driving situations. It is here disclosed a gear change, in which the source gear (first gear) and the target gear (second gear) are assigned to different clutches or input shafts - ie the first gear, the first clutch and the second gear, the second clutch. The shift sleeves associated with the two gear stages are first engaged and then engaged at the same time, with the clutches being simply intersected during the gear change itself. The two gear stages are thus so-called "upstream". In order to switch on the shift sleeve of the target gear, the speed of the two gear shift parts of the target gear by means of the second clutch or a synchronizer are synchronized in advance. DE 196 31 983 C1 does not disclose the situation when a gear change between two gear ratios associated with a clutch must be performed. In this situation, the second gear stage associated shift sleeve can not be synchronized in advance and inserted, because the first gear stage associated shift sleeve is engaged and transmits the torque of the motor. During the gear change between two of the same (first) clutch associated gear ratios, this clutch must be opened, designed the first-stage shift sleeve and the second speed gear shift sleeve are inserted. Only then can the first clutch be closed again or transmit a torque. Disadvantage of this method is that no torque is transmitted to the output shaft during this period, which the driver receives as very uncomfortable.

The invention is therefore based on the object that the aforementioned method in such a way and further, that the control of the engine speed during the gear stage change realized in another way, vzw. simplified and made more comfortable.

The aforementioned object is now achieved in that the control of the engine speed during the gear stage change takes place with the aid of at least one of the two friction clutches. Although the two friction clutches are always controlled according to a gear stage change, namely to realize the gear stage change, in the prior art, these vzw. then each fully open or closed, but now with the help of at least one of the two friction clutches, the engine speed is controlled accordingly during the gear stage change, at an upshift of the transmission, the engine speed vzw. reduced, so that the engine speed is adapted to the now then to be inserted next higher gear ratio accordingly. Since now with the aid of at least one of the two friction clutches, the engine speed is controlled eliminates the otherwise usual control effort on the engine control unit - at least during the gear stage change - the control of the engine speed during the gear stage change with a friction clutch, which anyway in the claimed here dual-clutch transmission during a Gear change must be controlled by the transmission control unit. Another advantage of the engine speed control described here with the aid of at least one of the two friction clutches in combination with the specific embodiment of the dual-clutch transmission preferred here is that the gear ratio change vzw. is realized so that always a torque applied to the transmission output shaft. In other words, the transmission output shaft is never completely torque free even during the gear stage change. Large "load changes" are thereby avoided. As a result, the disadvantages described above are substantially reduced.

There are now a multitude of possibilities for designing and developing the method according to the invention. For this purpose, reference may first be made to the claims subordinate to claim 1. In the following, the method according to the invention will now be explained in more detail with reference to a following drawing and the associated description. In the drawing shows

1 the dual-clutch transmission controlled according to the inventive method in a schematic schematic representation,

2a - 2 B a schematic representation of the principle of the method according to the invention, realized in an upshift,

3 a sliding sleeve or a ratchet wheel of a gear pair with corresponding respective dog teeth shortly before the engagement of the sliding sleeve in a partially sectioned schematic representation and

4 this in 1 illustrated dual-clutch transmission with the individual further components for implementing the method according to the invention.

The 1 to 4 show a dual-clutch transmission 1 or flow diagrams to illustrate the method according to the invention for controlling this dual-clutch transmission 1 ,

The 1 and 4 show here a schematically illustrated dual-clutch transmission 1 with two input shafts, namely a first input shaft E ₁ and a second input shaft E ₂ . The first input shaft E ₁ is associated with a first friction clutch K ₁ , wherein the second input shaft E _{2 is associated with} a second friction clutch K ₂ . The dual-clutch transmission shown here 1 is driven by an internal combustion engine whose crankshaft 2 is shown schematically. The two friction clutches K ₁ and K ₂ have a common outer clutch basket 3 and are arranged concentrically next to each other. About the friction plates provided here 4 respectively. 5 is the first input shaft E ₁ and the second input shaft E ₂ with the clutch basket 3 or the crankshaft 2 connectable to transmit a corresponding torque. The first input shaft E ₁ is formed here as a solid shaft. The second input shaft E ₂ is designed here as a hollow shaft and surrounds the first input shaft E _first

The dual-clutch transmission shown here 1 has a total of 6 gears, ie 6 gears. Each gear is formed by a pair of gears. Here are the gear pairings ➀ to ➅ for the individual corresponding gears. The drive wheels of the gear ratio ➀ and ➅ are firmly connected to the first input shaft E ₁ . The output wheels of these gears are vzw. designed as a needle bearing idler wheels, which have a first sliding sleeve 6 correspondingly effective with the output shaft 7 can be connected. The drive wheels of gears ➂ and ➃ are vzw. also designed as a needle bearing idler wheels, which have a second sliding sleeve 8th can be effectively connected to the first input shaft E ₁ . The output gears of gears ➂ and ➃ are fixed to the output shaft 7 connected. The drive wheel of gear ➄ is as vzw. designed as a needle-bearing idler gear and a third sliding sleeve 9 with the first input shaft E ₁ operatively connected, wherein the output gear of the gear ➄ fixed to the output shaft 7 connected is. The gear stage ➅ has a gear pair with two gears, wherein the first gear with the second input shaft E ₁ and the second gear fixed to the output shaft 7 connected is. Finally, a reverse gear ^{® is} provided, which will not be discussed here in detail.

4 shows a schematic representation of an engine control unit 10 for controlling the engine, not shown here, a transmission control unit 11 for controlling the processes in the dual-clutch transmission 1 and a servo unit 12 for controlling the corresponding movements of the sliding sleeves 6 . 8th . 9 and the friction clutches K ₁ and K ₂ . To control the movement of the sliding sleeve 6 . 8th . 9 and the friction clutches K ₁ and K ₂ are provided corresponding here not shown actuators.

The method according to the invention will now be explained in more detail by way of example for the gear ratio change from the first gear to the second gear, that is to say from the gear stage ➀ to the gear stage ➁. It may be noted at this point that the term first or second gear not specifically the first gear ➀ or the second gear ➁ is meant, but that here the gear stage change between two different of the total existing gears is meant, so the gear stage change From a first to a second gear stage here basically between the existing gears ➀ to ➄ can be done.

Before on the 2a to 2d discussed in more detail and the method of the invention is explained, may shortly before the 3 be explained in more detail. The 3 shows a schematic representation - partially cut - a sliding sleeve, here the sliding sleeve 6 and the corresponding ratchet wheel here at least partially with this sliding sleeve 6 to be brought in corresponding gear pair. Good to see is that both the sliding sleeve 6 as well as the unspecified shift wheel, so the shift gears ("ratchet" = part of the respective gear pair which can be brought into engagement with the sliding sleeve) and the sliding sleeve shown here 6 itself has an intermeshable - here clearly visible - dog teeth. So not just the usual otherwise usual in the art roof pitches, but here are just front pages available. From the 3 It can be seen that the respective end faces of the sliding sleeve and the ratchet wheel are flat (flat) and also only a meshing of the sliding sleeve in the ratchet wheel is possible if a corresponding positioning, namely "displacement" between sliding sleeve and ratchet is achieved here vzw. the sliding sleeve is always engaged under the concern of a differential speed, so that such a "shift" is always realized, which will be explained in more detail below.

Based on 1 and 4 Now is the inventive method for controlling the double gear 1 be explained in more detail with the two input shafts E ₁ and E ₂ . With the help of each friction clutch K ₁ and K ₂ is in each case a drive train feasible, wherein the crankshaft 2 via the friction clutches K ₁ and K _2, a motor torque to the respective drive train to the output shaft 7 is transmitted. For this purpose, the transmission must have at least two gear ratios, that shown here dual-clutch transmission 1 , the vzw. is designed as an automatic transmission, here has a total of six (ie with reverse gear seven) gear ratios. Here are the gear ratios ➀, ➁, ➂, ➃ or ➄ through the first sliding sleeve 6 , the second sliding sleeve 8th and the third sliding sleeve 9 inserted accordingly.

So far, it is common in the prior art that the engine speed of the engine, not shown, is changed depending on the gear ratio to be engaged, namely according to the engine speed and the engine torque to the gear stage to be engaged during the gear stage change via the engine control unit 10 is adjusted accordingly. In the method according to the invention described here, another principle is now realized, namely the control of the engine speed during the gear stage change is realized by means of at least one of the two friction clutches K ₁ and K ₂ , this inventive method is closer from the schematic sequences of 2a to 2d clear and should now be described in more detail at the gear stage change from first gear ➀ to second gear ➁:
2a now shows the realization of the gear stage change from the first gear ➀, the "source gear" to the second gear ➁, the "target gear". The dashed vertical lines represent the time of disengagement or engagement of the corresponding sliding sleeve, here the first sliding sleeve 6 Already from the 2a can be seen that between the gear change here the sixth gear ➅ for the duration of the disengaged sliding sleeve 6 "Inserted" remains, which will become clearer in the following.

A great advantage of the invention is that under concern of a differential speed, vzw. in a pull upshift, the sliding sleeve 6 , or the other sliding sleeves 8th respectively. 9 be engaged at the appropriate gear stage changes. This results in the upshift an "acceleration" for the driver, who is much more pleasant than, for example, a push. Vzw. should therefore insert the appropriate sliding sleeves 6 . 8th , and 9 always done "over-synchronous", so that the crankshaft 2 the engine is braked slightly at the moment of insertion of the sliding sleeves and the excess energy leads to an acceleration pressure in the vehicle.

Before on the 2 B to 2d is discussed in more detail, should be to the 1 and 4 again briefly explained that when the first gear engaged, here the first gear ➀ the drive train through the first closed friction clutch K ₁ , the first input shaft E ₁ , the first gear pair for the first gear ➀ and the output shaft 7 is formed. When engaged second gear, so inlaid second gear ➁, so appropriately shifted first sliding sleeve 6 from right to left, the drive train through the first closed friction clutch K ₁ , the first input shaft E ₁ , the second gear pair, namely the second gear pair for the second gear ➁ and the output shaft 7 educated. As the 2c shows is during the gear stage change from the first to the second gear, namely from the first gear ➀ to second gear ➁ the circuit now realized so that always a torque at the transmission output shaft and the output shaft 7 is applied. This is realized that during the gear position change, the second friction clutch K ₂ is closed at least partially, and a drive train through the second friction clutch K _2, the second input shaft E _2, a third gear pair, namely here the gear pair for the sixth gear ➅ and the output shaft 7 is formed. The output shaft 7 is therefore not torque free during the gear stage change.

During the gear stage change now the second friction clutch K _{2 is} at least partially closed, the torque from the crankshaft 2 via the second input shaft E ₂ , via the third gear pair (for the sixth gear ➅) to the output shaft 7 transmitted and the engine speed ω, in 2 B is shown, changed, namely thereby reduced. It is from the 2 B and 2d to recognize that prior to engagement of the corresponding first sliding sleeve 6 , represented by the dashed line running perpendicularly to the right, a certain differential speed is present or at the input shaft E ₁ then - when the target gear is engaged - a correspondingly higher torque is applied. In a gear stage change, the second friction clutch K _{2 is} closed and / or opened in such a way, namely so controlled that this torque 1 the first input shaft E ₁ takes over when this torque 1 the first input shaft E ₁ has taken over substantially completely, then the sliding sleeve from the first gear, here the first gear ➀ is disengaged, the second friction clutch K _{2 is} still further closed and even more torque 1 takes over, thereby simultaneously the engine speed ω is reduced and synch in the transmission of a certain torque M. on the second friction clutch K _2, the sliding sleeve 6 in the second gear, here the second gear ➁ is engaged, and the second friction clutch K _{2 is} thereby opened. This procedure just described is well, among others 2d to recognize.

As a result, by the corresponding control, here the closure or opening of the second friction clutch K _2, the engine speed - as out 2 B seen - controlled accordingly, namely on the einzulegende second gear, here the second gear ➁ adapted, so that the engine control unit 10 During a gear stage change just not the speed of the engine must control and this is done via one of the friction clutches, here the friction clutch K ₂ . For the rest of the control of the engine, ie the engine speed and the engine torque is the engine control unit 10 provided naturally, being used to control the transmission 1 the transmission control unit 11 as well as for actuating the sliding sleeves 6 . 8th and 9 at least one servo unit 12 is provided. Although it may be mentioned here, but need not be further explained that the corresponding control circuits in the transmission control unit 11 or engine control unit 10 based on electrical / electronic basis and cause the corresponding procedures. It may be mentioned at this point that, of course, the usual controls, such as control lines, speed sensors, regulators, actuators, etc. are provided and with their help then the inventive method in the automatic dual clutch transmission shown here 1 is realized.

As a result, a simplification of the control of the engine speed during a gear stage change is achieved by the inventive method, which reduces the disadvantages described above.

LIST OF REFERENCE NUMBERS

1

Double clutch

2

crankshaft

3

clutch basket

4

friction plates

5

friction plates

6

first sliding sleeve

7

output shaft

8th

second sliding sleeve

9

third sliding sleeve

10

Engine control unit

11

Transmission Control Module

12

servo unit

E ₁

first input shaft (full wave)

E ₂

second input shaft (full wave)

K ₁

first friction clutch

K ₂

second friction clutch

Claims (7)

Method for controlling a dual-clutch transmission ( 1 ) with two input shafts (E ₁ , E ₂ ) wherein the first input shaft (E ₁ ) a first friction clutch (K ₁ ) and the second input shaft (E ₂ ) is assigned a second friction clutch (K ₂ ) and with the aid of each friction clutch (K ₁ , K ₂ ) in each case a drive train can be realized, wherein of the friction clutches (K ₁ , K ₂ ) an engine torque from the respective input shaft (E ₁ , E ₂ ) via the respective drive train to the output shaft ( 7 ), wherein the transmission ( 1 ) has at least two gear ratios, the first gear at least by a first gear pair and the second gear at least formed by a second gear pair and wherein the gear stage change by the disengagement and / or engagement of at least one at least partially engageable with the first or second gear pair sliding sleeve ( 6 . 8th . 9 ) and wherein the engine speed (ω) is changed depending on the gear ratio to be engaged, wherein the control of the engine speed during the gear stage change by means of at least one of the two friction clutches (K ₁ , K ₂ ) is characterized in that the drive train both in the engaged first gear stage and in the engaged second gear, the first closed friction clutch (K ₁ ), and that during the gear stage change from first to second gear, the second friction clutch (K ₂ ) is at least partially closed and the drive train via the second friction clutch ( K ₂ ), the second input shaft (E ₂ ), a third gear pair and the output shaft ( 7 ) is formed. Method according to Claim 1, characterized in that , when a differential speed, vzw. in a pull upshift, the sliding sleeve ( 6 . 8th . 9 ) is indented. A method according to claim 1 or 2, characterized in that the switching toothing, namely the part of the respective gear pair, with the sliding sleeve ( 6 . 8th . 9 ) is engageable, and the sliding sleeve ( 6 . 8th . 9 ) itself has intermeshable dog teeth. Method according to one of the preceding claims, characterized in that during the gear stage change from the first to the second gear stage, the circuit is realized so that always a certain minimum torque on the output shaft ( 7 ) is present. Method according to one of the preceding claims, characterized in that during the gear stage change the second friction clutch (K ₂ ) is at least partially closed, the torque from the second input shaft (E ₂ ), via the third gear pair to the output shaft ( 7 ) is transmitted and the engine speed (ω) changed, in particular reduced. Method according to one of the preceding claims, characterized in that during a gear stage change, the second friction clutch (K ₂ ) is closed and / or opened, namely controlled, that this assumes the torque of the first input shaft (E ₁ ), if this torque of the has substantially completely taken over the first input shaft (E ₁ ), then the sliding sleeve ( 6 . 8th . 9 ) is disengaged from the first gear, the second friction clutch (K ₂ ) is further closed and takes even more torque, while the engine speed (ω) is reduced and at a certain torque (M sync.), the sliding sleeve ( 6 . 8th . 9 ) is engaged in the second gear and the second friction clutch (K ₂ ) is opened. Method according to one of the preceding claims, characterized in that an engine control unit ( 10 ) and for controlling the transmission ( 1 ) a transmission control unit ( 11 ) and for actuating the sliding sleeves ( 6 . 8th . 9 ) at least one servo unit ( 12 ) are provided.

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